UrlsWorker/src/main/java/eu/openaire/urls_worker/util/AssignmentHandler.java

package eu.openaire.urls_worker.util;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import eu.openaire.urls_worker.models.Assignment;
import eu.openaire.urls_worker.models.Task;
import eu.openaire.urls_worker.models.UrlReport;
import eu.openaire.urls_worker.payloads.requests.AssignmentRequest;
import eu.openaire.urls_worker.payloads.responces.WorkerReport;
import eu.openaire.urls_worker.plugins.publicationsRetriever.PublicationsRetrieverPlugin;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;

import java.util.*;


public class AssignmentHandler {

    private static final Logger logger = LoggerFactory.getLogger(AssignmentHandler.class);

    public static boolean isAvailableForWork = true;

    public static List<UrlReport> urlReports = null;


    public static Assignment requestAssignment()
    {
        RestTemplate restTemplate = new RestTemplateBuilder().build();
        String url = "http://localhost:8080/api/urls/test?workerId=" + WorkerConstants.WORKER_ID + "&tasksLimit=" + WorkerConstants.TASKS_LIMIT;
        String json = null;
        try {
            json = restTemplate.getForObject(url, String.class);
        } catch (Exception e) {
            logger.error("Could not retrieve the assignment: " + e.getMessage());
            return null;
        }

        AssignmentRequest assignmentRequest = null;
        ObjectMapper objectMapper = new ObjectMapper();
        try {
            assignmentRequest = objectMapper.readValue(json, AssignmentRequest.class);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }

        if ( assignmentRequest == null ) {
            String errorMessage = "Could not map the json to an \"assignmentRequest\"!";
            System.err.println(errorMessage);
            logger.error(errorMessage);
            System.exit(1);
        }

        //logger.debug(assignmentRequest.toString());   // DEBUG!

        Assignment assignment = assignmentRequest.getAssignment();
        logger.info("Assignment with id < " + assignment.getAssignmentId() + " > was received and it's ready to be processed. It contains " + assignment.getTasks().size() + " tasks.");
        // TODO - Maybe create a HashSet with these IDs. It may be useful for the Worker to know and report which assignments (and how many) it has processed.

        return assignment;
    }


    public static void handleAssignment()
    {
        Assignment assignment = requestAssignment();
        if ( assignment == null ) {
            logger.warn("The assignment was found to be null!");
            return;
        }

        // Start handling the assignment, the worker is busy.
        isAvailableForWork = false;

        List<Task> tasks = assignment.getTasks();

        // Iterate over the tasks and add each task in it's own list depending on the DATASOURCE in order to decide which plugin to use later.

        Multimap<String, Task> tasksForPlugins = HashMultimap.create();

        for ( Task task : tasks ) {
            // Add each task in its own HashSet.
            tasksForPlugins.put(task.getDatasource().getId(), task);
        }

        urlReports = new ArrayList<>(tasks.size()); // Define the new UrlReport-list. It is reinitialized each time.

        // TODO - Decide which tasks run with what plugin (depending on their datasource).

        // First run -in parallel- the tasks which require some specific plugin.

        // Then run the remaining tasks in the generic plugin (which handles parallelism itself).

        // For now, let's just run all tasks in the generic plugin.

        try {
            PublicationsRetrieverPlugin.processTasks(assignment.getAssignmentId(), tasksForPlugins.values());
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }

        postWorkerReport(assignment.getAssignmentId());

        isAvailableForWork = true;
    }


    public static boolean postWorkerReport(int assignmentId)
    {
        RestTemplate restTemplate = new RestTemplateBuilder().build();
        String url = "http://localhost:8080/api/urls/addWorkerReport";

        try {
            ResponseEntity responseEntity = restTemplate.postForEntity(url, new WorkerReport(WorkerConstants.WORKER_ID, assignmentId, urlReports), String.class);
            int responseCode = responseEntity.getStatusCode().value();
            if ( responseCode != HttpStatus.OK.value() ) {
                logger.error("Connection problem with the submission of the WorkerReport of assignment_" + assignmentId + " to the Controller. Error-code was: " + responseCode);
                return false;
            }
        } catch (Exception e) {
            logger.error("Error when submitting the WorkerReport of assignment_" + assignmentId + " to the Controller: ", e);
            return false;
        }

        return true;
    }

}